


Baby on the Way

by memoriesofrain



Category: The Umbrella Academy (TV)
Genre: Alpha Dave Katz, Alpha/Beta/Omega Dynamics, Alpha/Omega, Anal Sex, Bottom Klaus Hargreeves, Consensual Kink, Dirty Talk, Drug Addiction, Falling In Love, Family Fluff, Getting Clean, I Tried, Kinktober, Kinktober 2019, Knotting, M/M, Male Lactation, Marriage, Mpreg, NSFW, Nipple Play, Omega Klaus Hargreeves, Omega Verse, Post Mpreg, Pregnancy, Pregnancy Kink, Recreational Drug Use, Rehab, Rimming, Top Dave, but I'm kinda proud because I think this is the best smut I've written, in which Dave definitely has a pregnancy kink and klaus goes with it, never thought I'd write something like this, obviously
Language: English
Status: Completed
Published: 2019-10-12
Updated: 2019-10-12
Packaged: 2020-12-13 22:07:41
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,644
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21004916
Author URL: https://archiveofourown.org/users/memoriesofrain/pseuds/memoriesofrain
Summary: Klaus meets Dave Katz during his third stint in rehab and falls in-love with the gentlemanly alpha. The two become a family, then two becomes four with a fifth member on the way.ORKlaus and Dave fall in love, get married, and Dave has a pregnancy kink that Klaus is A-okay with.





	Baby on the Way

**Author's Note:**

> This is my longest kinktober piece yet, even if it is three days of prompts! I think this turned out okay? Never written this kink before but I enjoyed writing it, surprisingly. I hope you enjoy it!
> 
> Day 10: Pregnancy  
Day 11: Lactation  
Day 12: A/B/O

If you had told Klaus five years ago he’d be married to a good southern boy and have two, soon-to-be three, kids with said southern boy, he’d have laughed his ass off and asked what drugs you’d taken because it must have been the really _good_ stuff.

Klaus had met Dave in rehab, well more accurately, he met Dave on his fourth stint in rehab fresh off an overdose. He was twitchy as could be, hair matted to his forehead with sweat, nose running and sleep deprived. According to Ben, he looked like more of a mess than he usually did. So exactly how he wanted to look when meeting a handsome man like Dave.

David Katz stayed in the room across from him at the facility and had been there for five days before Klaus showed up. Dave didn’t come off as a druggie, hell he looked like your typical white picket fence, all-American family man. Klaus told him as such which made the man laugh.

“Yeah, I guess I do,” Dave admitted with a grin. “Served in the army in Iraq for a few years, came back and everything was different. I was different.” He shrugged, but his eyes looked faraway. “I didn’t handle that change well. Felt like everything was too much and turned to pills. I started with an actual prescription of Ativan, but once I ran out of refills I bought benzos from some guy I found on the street.”

“That’s usually what happens,” Klaus said from his seat on the couch in the common area. It was late and only the stragglers were left so Klaus and Dave hadn’t worried about talking. “I started with the little stuff and then sorta tumbled into the harder stuff at full throttle once I had a taste of ‘em.”

“When I started using I didn’t expect it to take over my life,” Dave let out a scoff, “I guess everyone thinks that when they start. That you won’t become addicted because you have it under control.”

“But you don’t.”

“But you don’t.”

They sat in companionable silence, well not for Klaus because there was a screeching woman yelling at the bored looking orderly near the nurse station. But other than that, yeah silence. Ben had wondered off somewhere when he’d started talking to Dave, saying he didn’t want to watch Klaus embarrass himself when he tried to flirt or some bull.

“What made you start?” Dave asked, breaking the silence. “You don’t have to tell me if you don’t want, but thought I’d ask in-case you wanted to share.”

Klaus gnawed on his bottom lip, shrugging his shoulders. “My whole life’s been one big fuckfest,” Klaus said, “and not even the good kind.” He grinned when Dave laughed at his description and gave himself a point in charming Dave. “If you really wanna know,” he paused for dramatic effect, “I see dead people.”

Dave shoved his shoulder. “Come on, Klaus, be serious.”

“I am being serious! Believe me I would not even joke about this if I wasn’t.” Klaus leaned his head back against the couch with a sigh. “You ever see those Umbrella Academy kids? The superheroes or whatever they were called?” He held his ‘hello’ hand out to Dave. “Nice to meet you, I’m Number Four, the Séance.”

Dave stared at him for a few moments, but took Klaus’s hand in his. “Shit, Klaus, that’s…”

“Fucking terrible?”

“Fucking terrible.”

Dave didn’t let go of his hand though, just lazily rubbed against the back of Klaus’s hand with his thumb. The tenderness wasn’t something Klaus was used to, but he ached for it. He wasn’t about to get Dave to stop anytime soon.

From there he and Dave fell into an easy relationship. It was easy to talk to the alpha in a way Klaus had never gotten from another person besides maybe Ben. They went through the rest of their stay in rehab, getting to know each other and learning what triggered their cravings for drugs. Dave suffered from PTSD and was usually triggered by flashbacks, loud noises, or nightmares. Klaus did his best to help Dave, waking the man up when he started having a nightmare, patiently talking Dave down from a flashback with the softest voice he’d ever used. As for loud noises, Klaus didn’t have a solution for that but Dave shrugged it off, touched that Klaus had even tried in the first place.

Klaus’s triggers were obviously the ghosts. And the mausoleum. Fuck that place and he hopes his dear ol’ dad gets an economy class ticket to Hell. But just like he was patient with Dave, Dave was patient with him. The alpha whispered reassuring words when Klaus became overwhelmed by the voices of all the ghosts around him, coaxing Klaus into practicing with his powers.

It was slow going because Klaus hadn’t the foggiest idea on how to even go about figuring out his powers when his father had failed to do so in all the years he was under the man’s thumb. But slowly, much later than when their stint in rehab was over, he started to get a grip on his powers. He first learned to make Ben solid and the two had cried like babies at being able to hug after all this time. He was able to introduce Ben and Dave that day and he felt happiness bubble in his chest at being able to officially introduce his two favorite people.

From there he learned how to help ghosts pass on. It was tiring, but the more he did it the less tiring it became and soon he was able to keep the ghosts away unless he wanted them around.

Klaus and Dave continued to grow closer, soon Klaus moved in with Dave in a little apartment. He got a part-time job at the bakery about a block away from their apartment, working the counter and decorating cakes and cupcakes in brilliant colors and designs. Dave had a full-time job as a contractor, but the alpha came home every afternoon with a smile and a hello kiss.

By the time their anniversary rolled around they were engaged. Klaus had sent out invitations to all his siblings to come to his wedding, but he only heard back from Vanya and Diego. The two had been understandably shocked that Klaus of all people was getting married, but they were happy for the omega.

The wedding was small and intimate, but Vanya, Diego, and Ben were there to support Klaus and Dave’s family welcomed him to the family with open arms. It was when Dave’s mom brought up the topic of grandchildren that things became interesting.

“Just wondering when you two would be giving me grandchildren,” Dave’s mother said, her eyes bright and happy.

Dave choked on his drink, his face flushing red and giving his mother a wide-eyed look. “Ma, don’t give us the grandkids talk, we just got married,” Dave complained half-heartedly.

Klaus looked up at Dave, and saw how his husband’s eyes went to Klaus’s stomach before blushing harder and turning his attention back to his mom. Oh, he knows exactly what the alpha was thinking about and Klaus grinned wickedly. “Well it’s really up to Dave when he puts a bun in this oven,” Klaus said, putting a hand against his stomach over his white pantsuit.

Dave’s wide-eyed stare went to Klaus’s and he could see the alpha searching his eyes for a hint of a lie. But Klaus wasn’t. It surprised him, but he genuinely loved the idea of making a family with Dave. He didn’t know if his past with drugs would do anything, but they’d both been clean for over a year at that point and he figured they’d just have to do some research to make sure.

But one thing was certain: Dave would probably not rest until Klaus was pregnant with his pup now that Klaus had stated he was fine with starting a family.

Before too long, Klaus got pregnant and nine months later he gave birth to a little boy they named Fievel Benjamin Katz, in honor of both Five and Ben. Ben might have got a little teary-eyed at the name, but Klaus didn’t tease him about it. Especially not when he was a blubbering mess crying about how beautiful his and Dave’s baby boy was.

Not too long after Fievel was born, he got pregnant again. Klaus thought he might be exasperated at getting knocked up again so soon after his last pregnancy, but Klaus felt sated and content. Dave doted on him and taking care of Fievel during his pregnancy seemed to come to Klaus naturally which was a relief because Klaus didn’t know how he’d react if started to neglect his first pup for the second one growing in his womb.

Sarah Katz was born a year after her older brother and Klaus and Dave loved her just as much as their firstborn. Raising her was different than how they’d raised Fievel, but they enjoyed learning how to best take care of their princess.

The family remained as the four of them for three years before Klaus got pregnant again. Dave was ecstatic, spinning Klaus around with a booming laugh and Klaus felt his heart warm at the sight of his husband so happy.

Klaus was truly blessed.

* * *

Klaus slowly wiggled his way to the edge of the bed he’d been napping on. Despite having gone through this twice before, he was always shocked at how hard it was to move around during the last month of his pregnancy. His belly was a dome above him and he knew he looked like he’d swallowed a watermelon. Ben liked to tease him enough about it and if Klaus hadn’t learned to brush those comments aside he’d be a crying mess.

With a groan he managed to get himself up and stumbled his way to the bathroom. Another joy of pregnancy: his bladder had shrunk by at least three sizes. His little jellybean loved kicking him and jostling around his bladder control so he had to be vigilant. Last time he’d peed himself he’d taken so many pills he thought he was a melting crayon.

Klaus did his business sitting down since he couldn’t see his dick to aim right. He’d tried during the first pregnancy and all that resulted in was Klaus having to clean their bathroom and Ben laughing at him.

Ben laughed at him for a lot of things.

After finishing and washing his hands he took the time to stare at himself in the mirror. Parenthood had settled nicely on him. He wasn’t drug-addict stick thin anymore, but he still never gained much weight. Besides his obvious midsection getting larger, he’d gained a little cushion in his hips and thighs “cushion for pushin’” as Dave called it. Klaus thought he’d be more bothered when his body started to change, but he felt fully content in the changes. He was creating life, a life made by him and Dave. It was probably all those omega hormones lighting fireworks in his mind, but Klaus didn’t care.

He loved being a dad with Dave. He loved being able to give this to Dave. To make a family with Dave.

He ran a hand down his bare stomach and laughed when a foot kicked at it. He liked playing this game with his little jellybean, chasing after the kicks with pokes from his fingers. So distracted by his game he didn’t notice Dave peak his head in.

“Playing with our bean, dove?” Dave asked, stepping into the bathroom and wrapping his hands around Klaus’s waist.

Klaus snuggled into Dave’s arms. “They’re being particularly active today,” Klaus said with a flap of his hands. “Was hoping if I played with them for a bit they’d let me take a nap or something.”

Dave nuzzled his face into Klaus’s neck. “Hmm, little bean you gotta leave your papa alone, how’s he supposed to help me take care of your brother and sister if you keep tiring him out?”

Klaus snorted. “You _all_ tire me out.” Klaus turned his head and pressed his lips against Dave’s temple. “But I love you all for it.”

Dave rumbled happily, squeezing his arms tighter around Klaus and kissing along the omega’s neck. “You’re perfect, y’know that?”

“Well you sure do know how to flatter a man.” Klaus turned his head to capture Dave’s mouth with his own. It started off tender, their lips moving against each other in a sensual slide before Klaus slipped his tongue into Dave’s mouth. From there it was a dance of their tongues against each other with purpose trying to map out the geography of the other’s mouth. Klaus bit softly at Dave’s tongue getting a groan from the alpha.

Dave ended the kiss with a gasp of air, panting against Klaus’s mouth. Dave’s pupils were blown and a flush was dusting at the tips of his ears. Klaus always thought Dave looked adorable when his arousal started.

Dave’s hands were still around Klaus’s waist, his palms cupping Klaus’s belly with strong hands. Klaus would be perfectly happy staying like this for the rest of the evening if his feet wouldn’t be killing him by then. And he wasn’t horny as hell to have Dave fuck him into the mattress.

Klaus shifted in Dave’s arms before arching his back, grinding his ass against Dave’s growing erection. Just the feel of the semi-hard impression of Dave’s cock against his brief clad ass had slick trickling out of his hole. Like he expected, Dave instantly ground his cock harder against Klaus. Dave could never resist the smell of Klaus’s arousal, especially once he got pregnant the first time.

Apparently Klaus usually smelt like orange crème and snickerdoodles but whenever he was pupped, his scent had the added notes of milk and honeysuckle. It was a soft scent that had made Dave knot before they’d even gotten to the good part the first time the alpha had smelt it. Klaus laughed at the time, but it made pride fill his chest that he had caused Dave to react like that.

“Y’need me to take care of you, Klaus?” Dave asked, holding his hips tightly against Klaus’s. “Need something to fill that needy hole of yours?”

Klaus moaned tilting his head to expose more of his neck in a show of submission. “Need you so badly, alpha. Need you to fill me up, stuff me with your knot. Breed me.”

Dave pressed his palm tighter against Klaus’s bump. “Already bred you up nice and good, dove.” Despite the cocky, but true, statement Dave’s cock twitched in interest against Klaus’s ass.

Klaus stared at Dave’s eyes through the mirror. “You don’t wanna try getting me knocked up again before this one’s even out?” Klaus flexed his muscles to push his stomach out a little more. “Don’t wanna try making this one a twin?”

“You know that’s not how it works.”

“Doesn’t mean I don’t want it.” Klaus grinned and gave Dave a wink. “Know you want it too, alpha. Wanna watch me come undone on your knot, dripping slick wetting my thighs. Wanna see my belly get just a little bit bigger, watch my tits leak milk down my chest.”

Dave moaned, biting at the mating mark on Klaus’s scent gland. “Klaus, you’re gonna make me cum before we even get started.”

Klaus giggled. “Wouldn’t be the first time, babe.” The alpha swatted at Klaus’s ass, earning a squeak from the omega as the action caused more slick to gush out of his, soaking his briefs. “Fuck me, already soaked through these, stupid hormones.” That was a lie, he loved that he got aroused so quickly and that his body was always ready to handle his needs.

His alpha toyed at the waistband of Klaus’s briefs. “Guess you’ll have to take them off.”

“Or you could.”

Dave didn’t need to be told twice, getting on his knees and pulling the only garment on Klaus off of him. Klaus dutifully stepped out of them once they’d been pulled all the way down, glad that the wet briefs were off him. His husband didn’t move from his spot on the floor, instead spreading Klaus’s cheeks apart and blowing on his hole. Klaus shivered at the cool breath on his weeping hole, pushing his hips back into Dave’s hold.

“Such a pretty thing,” Dave muttered, pressing a kiss to the puckered entrance. Dave licked up the slick running down Klaus’s taint towards his balls, savoring the breathy whines and moans coming from Klaus as Dave continued his ministrations. Pointing his tongue, he drove his tongue into Klaus’s hole. There was no resistance in the first push but Klaus’s ring of muscles quickly clung to the intrusion. Dave chuckled a little, working Klaus’s hole with his tongue, lapping up the slick that was practically gushing inside of the omega.

“C-christ on a cracker, Dave,” Klaus moaned, leaning over the counter as best he could with his belly in the way. He stared at himself in the mirror, taking in the flush that went all the way to his tits, milk beading at his nipples that threatened to trail down his torso. The gravid expanse of his belly hung from his hunched frame, completely blocking the sight of his cock. He didn’t expect to get off on the sight, but it made his inner omega purr with delight. His alpha had bred him _so well_. “Need more, alpha. Please, please, fingers, dick, knot, please need something more.”

Dave pulled away from his task of rimming Klaus. He’d love to take more time to tease Klaus, but he knew that his mate would be more comfortable if they continued in their bed. Standing up, he grabbed Klaus’s shoulders and slowly brought the man back into an upright position. He couldn’t help but smile at Klaus’s noise of protest, turning the man around to get his mouth back on Klaus’s.

Klaus could taste himself against Dave’s lips and hummed faintly at the flavor of his own slick mixed with Dave’s natural flavor. Dave loved how he tasted and Klaus loved how Dave tasted. It made sixty-nine-ing more than an enjoyable experience. 

Klaus let himself be directed to his and Dave’s bed where his alpha helped lower him to the bed with a huff from the omega. He watched with rapt attention as Dave began stripping out of his clothes. He watched as more of Dave’s skin was revealed, licking his lips and wiggling his eyebrows invitingly getting a snort of laughter from Dave. Klaus stuck his tongue out at his husband, circling his nipples with his forefingers. He tweaked his left nipple and hissed when the beading milk increased to a drip down from his chest to the sheets under him.

He started lactating a week ago and already his tits were swollen and heavy with milk. He’d always produced a surplus of the stuff as if his body assumed he was going to have to feed two pups instead of one. But Dave was all too happy to assist him in relieving the pressure that his bundles of joy couldn’t finish. Which is exactly why he kept playing with the aching buds because if he could convince Dave to move faster he was going to use any means necessary to get him to do so. He smirked at Dave and spread his legs wider, moaning as he pinched both of his nipples.

His alpha practically ripped off his pants in his haste to climb on top of Klaus and the omega continued his ministrations until Dave was kneeling over him and pushing aside Klaus’s hands, taking one of Klaus’s nipples in his mouth and suckling at the teat. Klaus moaned loudly as he felt his milk letdown increase, watching as Dave swallowed down mouthfuls steadily. His husband made sure to intersperse soothing passes of his tongue over the abused nub before switching sides and beginning to suckle again.

Klaus tried to arch his chest further into Dave’s mouth but the alpha pinned him down with sure hands, rubbing at tense muscles like the best husband in the world. “Dave, I’m like five seconds away from cumming if you don’t stop soon,” Klaus panted.

Dave released Klaus’s teat with a pop, licking up any of the remaining milk around his mouth. “Then cum, baby, I’m not gonna be done with you for a while yet,” Dave reassured, “But I can always pull out that ring we got if you’d prefer not to.”

Just the thought of Dave slipping the cock ring around his dick had him cumming with a cry of Dave’s name. His dick spurted white ropes along the underside of his belly, unable to make it over the hump to reach his chest.

His alpha grinned at him, petting a hand through his sweaty curls, brushing a longer piece behind his ear. “Good boy, feel better?” Dave asked.

Klaus nodded, running his hands across Dave’s shoulders and down Dave’s back. “Yeah, but I still want more,” he admitted.

“You’re insatiable.”

“If I’m insatiable what does that make you?”

Dave leaned over to press his mouth close to Klaus’s ear. “Never said I wasn’t insatiable too.” He kissed down Klaus’s chest to his belly, lazily kissing the stretched flesh. His hands followed the flow of Klaus’s body until he reached just above the man’s hips and was cupping Klaus’s belly. He felt a kick against his right hand and gave the spot an extra kiss.

“Our bean hasn’t calmed down yet? Figured they’d have tired themselves out at this point.”

Klaus shook his head. “Nah, they seem to have endless energy,” Klaus said.

“You okay to continue? We can just snuggle if you want.”

If Klaus could move like he used to he would’ve switched places with Dave and sat on the alpha, but he settled for grinding up against Dave’s cock, moaning at the friction. “Don’t even think about it.” Klaus’s cock was struggling to get hard again, but Klaus knew it wouldn’t be too long for him to recover from his orgasm. “It’s time for you to put that glorious cock of yours inside me.”

Dave finally seemed to realize how badly he needed Dave because his alpha tapped his hip. “You wanna be on your hands and knees or you wanna lay down on your side?” Klaus was too far in his pregnancy for them to be able to comfortably be able to have sex face to face, unless Klaus was feeling up to riding Dave. But he always made Klaus decide how they did this or if it would happen at all.

The omega whined, pushing Dave away enough to flip himself over and onto his hands and knees. He spread his knees as much as he could and lowered his chest toward the bed to fully present his ass to Dave. His belly was just shy of brushing against the sheets and Klaus felt more slick flow out of him.

Dave made an appreciative sound in his throat, using one hand to spread Klaus’s cheeks just enough so he could stare at the winking hole. It always made Dave horny to see Klaus’s hole still fucked open from the night before. The hole flexed around nothing, impatient to suck whatever was put in it, in. “I’ve got you, darling,” Dave said, guiding his cock to Klaus’s hole with his free hand, “You’re still ready for my cock even though it’s been almost a full day since we last fucked. Such a perfect, beautiful omega.”

“Only for you, Dave. Only you,” Klaus moaned, as Dave’s cock started to push in. He relaxed as much as he could even if all of him wanted to clench around the alpha’s cock to keep it inside him. “Oh fuck.”

Dave didn’t stop pushing in until he bottomed out, his balls resting against Klaus’s ass. He hunched his body over Klaus’s, mouthing at Klaus’s shoulders and neck. “The best omega, love being filled with my alpha cock, don’t you? You love how I fill you up, how my knot feels when it locks us together?” Dave cupped the omega’s leaking chest, massage them and relishing in the keening whimpers that were coming out of Klaus’s mouth. “You were made for this, tits full of milk and your belly heavy with a pup.”

Klaus moaned, pushing his ass harder backwards to try to take even more of Dave in him. “Alpha, yes, meant to be full of your pups, take care of our family.”

Dave nuzzled against Klaus’s mate mark, nipping at the skin. “Wanna keep you like this always,” Dave admitted, rubbing circles against Klaus’s belly. “Wanna keep you barefoot and pregnant.” He ground his hips in little circles so he wouldn’t leave Klaus’s tight heat. “A pup on your breast and another in the oven.”

Heat seared in Klaus’s belly as he imagined what Dave was saying. He could see himself taking care of their kids, one of them in his arms as it suckled on his breast, his belly sitting heavy on his frame. He’d never had more than one pup at once, but he imagined being pregnant with more. How big his stomach would grow as he neared the end of his pregnancy. And Dave wanted to keep Klaus that way.

It wasn’t something that appealed to Klaus in everyday life; realistically they could only take care of so many kids before they’d be too overwhelmed, both physically and mentally but also financially. But in this moment Klaus had never heard a more arousing fantasy. “Do it, alpha,” Klaus whimpered, “Breed me. Wanna be full, wanna be bred. Knot me, need your knot me. Wanna have as many pups as you want.”

Dave’s shallow thrusts didn’t speed up, but they did feel deeper and Klaus moaned happily as Dave’s knot started to form. Dave was whispering dirty things against his neck, but Klaus couldn’t focus on his alpha’s voice. He was too caught up in the weight of his belly making his back arch and his breasts leaking as Dave continued to fuck him like he was in complete control of himself. “D-Dave I need to-“

“It’s okay baby, you can do it,” Dave reassured, rubbing his belly as he drove his hips in again, “Go ahead, cum for me.”

Klaus came with a guttural moan of Dave’s name, his dick releasing a pitiful amount of cum that dribbled to the sheets. Dave cursed softly as Klaus’s channel fluttered around him, driving himself as deep as he could into Klaus, his knot inflated to lock them together as he painted his omega’s walls with his cum.

Dave delicately maneuvered them so that they were on their sides, Klaus’s back pressed against Dave’s chest. Klaus sighed happily as he felt Dave’s cock fill him with more cum. He was going to be absolutely sloppy when Dave’s knot went down.

Sweet kisses were littered against his shoulders and Dave’s hands were protectively on Klaus’s belly, tenderly rubbing the bump again. “Can’t keep your hands off it, can you?” Klaus teased, turning his head to look at Dave.

Dave made a noncommittal noise, his eyes soft. “Don’t wanna keep my hands off you, dove.” He kissed Klaus’s cheek and snuggled closer. “I’m excited to meet this little bean when their ready to come out.”

Klaus laced their fingers together and smiled. “Just a few more weeks and they’ll be here.”

“Can’t wait.”

They had to go to sleep, especially because Dave’s sister was gonna bring their kids home in the morning from their stay with her, but they lavished in each other’s warmth, happy and sated and ready for the future.

**Author's Note:**

> Thank you so much for reading this! If you have time, I would greatly appreciate it if you left a comment telling me what you thought of this. 
> 
> If you have any prompts you'd like me to attempt, send them to my tumblr [cakelanguage](https://cakelanguage.tumblr.com)


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